Diff: main.cpp

Revision:

0:9aab4157fdae

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Nov 24 12:34:47 2013 +0000
@@ -0,0 +1,54 @@
+#include "mbed.h"
+#include "PCA9672.h"
+ 
+PCA9672 ioxp(P0_10, P0_11); //I2C connected to PCA9672 in LPC800-MAX
+ 
+Serial pc(USBTX, USBRX); // tx, rx
+
+static void experiment1_alt1()
+{
+    ioxp.frequency(100000);
+    ioxp.direction(0x80); // mark the push-button pin as input and the rest as outputs
+ 
+    while (1) {
+        uint8_t val = ioxp.read();
+        pc.printf("Reading 0x%02x - bit 7 is %d\n", val, val>>7);
+        if (val & 0x80)
+        {
+            ioxp.write(0x10);
+        }
+        else
+        {
+            ioxp.write(0x20);
+        }
+        wait(.50);
+    }
+}
+
+static void experiment1_alt2()
+{
+    ioxp.frequency(100000);
+    ioxp.direction(0x80 | 0x20); // mark the push-button pins (on breadboard and onboard) as inputs
+ 
+    while (1) {
+        uint8_t val = ioxp.read();
+        pc.printf("Reading 0x%02x - bit 7 is %d, bit 5 is %d\n", val, (val>>7)&1, (val>>5)&1);
+        if (((val & 0xa0)==0xa0) || ((val & 0xa0)==0x00))
+        {
+            // both or neither buttons are pressed
+            ioxp.write(0x10);
+        }
+        else
+        {
+            // exactly one of the buttons are pressed
+            ioxp.write(0x00);
+        }
+        wait(.50);
+    }
+}
+
+int main()
+{
+    //experiment1_alt1(); //onboard button controls yellow (pressed) and green (released) LEDs
+    experiment1_alt2(); //two buttons. Yellow LED lit with exactly one is pressed
+}
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